The detection of output state signals from highly capacitive, low drive current state indicating devices, such as a semiconductor memory, requires output signal levels from the device to be near the midrange of the trigger threshold of the sense amplifiers performing the detection operation. The output node of a cell in a semiconductor memory, such as for example a read only memory (ROM), can be connected directly to the sense amplifier.
However, such a directly connected arrangement would be unacceptably slow and unresponsive in producing a meaningful output, because the output node of the memory is highly capacitive. In particular, the output node would have to be slewed from a level near ground potential or the level of the device bias voltage, and beyond the trip point of the sensing circuit before a meaningful output indication could be established.
Accordingly, it is an object of the invention herein to develop a technique for clamping the output node of a semiconductor memory to permit effective output signal detection.